In a System in Package (SiP), a plurality of semiconductor chips are stored in a single package. For example, there has been proposed a semiconductor device in which the plurality of semiconductor chips are stacked up. In addition, the plurality of semiconductor chips may be arranged side by side in a lateral direction. The Input/Output (I/O) terminals of the plurality of semiconductor chips are joined together by bumps such as micro-bumps, for example. Since the micro-bumps allow the I/O terminals arranged at an interval smaller than the conventional I/O terminals to be joined together, it is possible to make a bus width of data transmitted between the semiconductor chips wider than the conventional bus width. Therefore, the semiconductor chips joined by the micro-bumps may realize a transmission speed higher than the conventional semiconductor chips.
Meanwhile, if a large number of I/O terminals are arranged, there is a possibility that a failure occurs in the wirings including the I/O terminals and the micro-bumps, due to the defective manufacture of the micro-bumps. For example, a failure may occur in which the wirings including the I/O terminals and the micro-bumps are opened or neighboring wirings may short-circuits.
In addition, if the interval between the I/O terminals is smaller than the convention I/O terminals, a test for the surroundings of the I/O terminals is sometimes carried out after the assembly (packaging) of the SiP, because it is difficult to carry out the test with the semiconductor chips themselves. Further, a reduction in a yield resulting from the defective joining by the micro-bumps becomes a big factor that incurs a high cost for the SiP.
Therefore, for example, a technology to detour a defective portion has been proposed in the semiconductor device in which the plurality of semiconductor chips is stacked up. Such a type of semiconductor device includes a spare signal path (hereinafter referred to also as a redundant wiring) and a redundant circuit changing the spare signal path. For instance, if one of a plurality of signal paths between the semiconductor chips develops a failure for several reasons such as a disconnecting portion, the spare signal path is used.
When any one of the signal paths between the semiconductor chips develops a failure due to short-circuits between the neighboring wirings, it is impossible to resolve the failure of the signal path between the semiconductor chips by the redundant wiring of one line. For example, if the short-circuit occurs between the neighboring wirings, the failure of the signal path between the semiconductor chips is resolved by using a redundant wiring of two lines instead of a wiring of two lines that causes a short-circuit. The detour of the defective portion using the redundant wirings of two or more lines leads to an increase in scale of the redundant circuit including, for example, a selector for selecting a wiring that is to be used.
The following is reference documents:
[Document 1] Japanese Laid-Open Patent Publication No. 2013-131534,
[Document 2] Japanese Laid-Open Patent Publication No. 2007-158237, and
[Document 3] International Publication Pamphlet No. WO 2010-097947.